RTC does not update the clock value when power supply is removed

Hi All,

I am working on RTC (DS1307)with atmega32.

RTC is working and updating values correctly when it has the 5V power supply.

But once power fails, it does not update the clock value. After power on, the RTC begins the updating sequence with last updated values.

For example, Before Power off, display shows 10:22:27:AM.
After 10 minute later i power on, Display begins with 10:22:27:AM

3V lithium battery is connected across DS1307.

Can any one give the solution to slove the this problem?

Expecting Feedback.

Thanks & Regards,
Santhanam

Is there 3 volts present on pin 3 with the power off ?
I know there should be
but have you checked with a meter ?

can you post your circuit? if your RTC is stopped (time is paused) it means clock is at halt somehow. just make sure your hardware design is not affecting RTC crystal.

I am facing same problem here
rtc not updating

i have connected battery negative terminal to main supply as its different power supply

Try changing the RTC..